linux/drivers/pwm/pwm-sunplus.c
Uwe Kleine-König 6c452cff79 pwm: Make .get_state() callback return an error code
.get_state() might fail in some cases. To make it possible that a driver
signals such a failure change the prototype of .get_state() to return an
error code.

This patch was created using coccinelle and the following semantic patch:

@p1@
identifier getstatefunc;
identifier driver;
@@
 struct pwm_ops driver = {
        ...,
        .get_state = getstatefunc
        ,...
 };

@p2@
identifier p1.getstatefunc;
identifier chip, pwm, state;
@@
-void
+int
 getstatefunc(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_state *state)
 {
   ...
-  return;
+  return 0;
   ...
 }

plus the actual change of the prototype in include/linux/pwm.h (plus some
manual fixing of indentions and empty lines).

So for now all drivers return success unconditionally. They are adapted
in the following patches to make the changes easier reviewable.

Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Acked-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221130152148.2769768-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2022-12-06 12:46:22 +01:00

235 lines
6.5 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* PWM device driver for SUNPLUS SP7021 SoC
*
* Links:
* Reference Manual:
* https://sunplus-tibbo.atlassian.net/wiki/spaces/doc/overview
*
* Reference Manual(PWM module):
* https://sunplus.atlassian.net/wiki/spaces/doc/pages/461144198/12.+Pulse+Width+Modulation+PWM
*
* Limitations:
* - Only supports normal polarity.
* - It output low when PWM channel disabled.
* - When the parameters change, current running period will not be completed
* and run new settings immediately.
* - In .apply() PWM output need to write register FREQ and DUTY. When first write FREQ
* done and not yet write DUTY, it has short timing gap use new FREQ and old DUTY.
*
* Author: Hammer Hsieh <hammerh0314@gmail.com>
*/
#include <linux/bitfield.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#define SP7021_PWM_MODE0 0x000
#define SP7021_PWM_MODE0_PWMEN(ch) BIT(ch)
#define SP7021_PWM_MODE0_BYPASS(ch) BIT(8 + (ch))
#define SP7021_PWM_MODE1 0x004
#define SP7021_PWM_MODE1_CNT_EN(ch) BIT(ch)
#define SP7021_PWM_FREQ(ch) (0x008 + 4 * (ch))
#define SP7021_PWM_FREQ_MAX GENMASK(15, 0)
#define SP7021_PWM_DUTY(ch) (0x018 + 4 * (ch))
#define SP7021_PWM_DUTY_DD_SEL(ch) FIELD_PREP(GENMASK(9, 8), ch)
#define SP7021_PWM_DUTY_MAX GENMASK(7, 0)
#define SP7021_PWM_DUTY_MASK SP7021_PWM_DUTY_MAX
#define SP7021_PWM_FREQ_SCALER 256
#define SP7021_PWM_NUM 4
struct sunplus_pwm {
struct pwm_chip chip;
void __iomem *base;
struct clk *clk;
};
static inline struct sunplus_pwm *to_sunplus_pwm(struct pwm_chip *chip)
{
return container_of(chip, struct sunplus_pwm, chip);
}
static int sunplus_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
struct sunplus_pwm *priv = to_sunplus_pwm(chip);
u32 dd_freq, duty, mode0, mode1;
u64 clk_rate;
if (state->polarity != pwm->state.polarity)
return -EINVAL;
if (!state->enabled) {
/* disable pwm channel output */
mode0 = readl(priv->base + SP7021_PWM_MODE0);
mode0 &= ~SP7021_PWM_MODE0_PWMEN(pwm->hwpwm);
writel(mode0, priv->base + SP7021_PWM_MODE0);
/* disable pwm channel clk source */
mode1 = readl(priv->base + SP7021_PWM_MODE1);
mode1 &= ~SP7021_PWM_MODE1_CNT_EN(pwm->hwpwm);
writel(mode1, priv->base + SP7021_PWM_MODE1);
return 0;
}
clk_rate = clk_get_rate(priv->clk);
/*
* The following calculations might overflow if clk is bigger
* than 256 GHz. In practise it's 202.5MHz, so this limitation
* is only theoretic.
*/
if (clk_rate > (u64)SP7021_PWM_FREQ_SCALER * NSEC_PER_SEC)
return -EINVAL;
/*
* With clk_rate limited above we have dd_freq <= state->period,
* so this cannot overflow.
*/
dd_freq = mul_u64_u64_div_u64(clk_rate, state->period, (u64)SP7021_PWM_FREQ_SCALER
* NSEC_PER_SEC);
if (dd_freq == 0)
return -EINVAL;
if (dd_freq > SP7021_PWM_FREQ_MAX)
dd_freq = SP7021_PWM_FREQ_MAX;
writel(dd_freq, priv->base + SP7021_PWM_FREQ(pwm->hwpwm));
/* cal and set pwm duty */
mode0 = readl(priv->base + SP7021_PWM_MODE0);
mode0 |= SP7021_PWM_MODE0_PWMEN(pwm->hwpwm);
mode1 = readl(priv->base + SP7021_PWM_MODE1);
mode1 |= SP7021_PWM_MODE1_CNT_EN(pwm->hwpwm);
if (state->duty_cycle == state->period) {
/* PWM channel output = high */
mode0 |= SP7021_PWM_MODE0_BYPASS(pwm->hwpwm);
duty = SP7021_PWM_DUTY_DD_SEL(pwm->hwpwm) | SP7021_PWM_DUTY_MAX;
} else {
mode0 &= ~SP7021_PWM_MODE0_BYPASS(pwm->hwpwm);
/*
* duty_ns <= period_ns 27 bits, clk_rate 28 bits, won't overflow.
*/
duty = mul_u64_u64_div_u64(state->duty_cycle, clk_rate,
(u64)dd_freq * NSEC_PER_SEC);
duty = SP7021_PWM_DUTY_DD_SEL(pwm->hwpwm) | duty;
}
writel(duty, priv->base + SP7021_PWM_DUTY(pwm->hwpwm));
writel(mode1, priv->base + SP7021_PWM_MODE1);
writel(mode0, priv->base + SP7021_PWM_MODE0);
return 0;
}
static int sunplus_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
struct sunplus_pwm *priv = to_sunplus_pwm(chip);
u32 mode0, dd_freq, duty;
u64 clk_rate;
mode0 = readl(priv->base + SP7021_PWM_MODE0);
if (mode0 & BIT(pwm->hwpwm)) {
clk_rate = clk_get_rate(priv->clk);
dd_freq = readl(priv->base + SP7021_PWM_FREQ(pwm->hwpwm));
duty = readl(priv->base + SP7021_PWM_DUTY(pwm->hwpwm));
duty = FIELD_GET(SP7021_PWM_DUTY_MASK, duty);
/*
* dd_freq 16 bits, SP7021_PWM_FREQ_SCALER 8 bits
* NSEC_PER_SEC 30 bits, won't overflow.
*/
state->period = DIV64_U64_ROUND_UP((u64)dd_freq * (u64)SP7021_PWM_FREQ_SCALER
* NSEC_PER_SEC, clk_rate);
/*
* dd_freq 16 bits, duty 8 bits, NSEC_PER_SEC 30 bits, won't overflow.
*/
state->duty_cycle = DIV64_U64_ROUND_UP((u64)dd_freq * (u64)duty * NSEC_PER_SEC,
clk_rate);
state->enabled = true;
} else {
state->enabled = false;
}
state->polarity = PWM_POLARITY_NORMAL;
return 0;
}
static const struct pwm_ops sunplus_pwm_ops = {
.apply = sunplus_pwm_apply,
.get_state = sunplus_pwm_get_state,
.owner = THIS_MODULE,
};
static void sunplus_pwm_clk_release(void *data)
{
struct clk *clk = data;
clk_disable_unprepare(clk);
}
static int sunplus_pwm_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct sunplus_pwm *priv;
int ret;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(priv->base))
return PTR_ERR(priv->base);
priv->clk = devm_clk_get(dev, NULL);
if (IS_ERR(priv->clk))
return dev_err_probe(dev, PTR_ERR(priv->clk),
"get pwm clock failed\n");
ret = clk_prepare_enable(priv->clk);
if (ret < 0) {
dev_err(dev, "failed to enable clock: %d\n", ret);
return ret;
}
ret = devm_add_action_or_reset(dev, sunplus_pwm_clk_release, priv->clk);
if (ret < 0) {
dev_err(dev, "failed to release clock: %d\n", ret);
return ret;
}
priv->chip.dev = dev;
priv->chip.ops = &sunplus_pwm_ops;
priv->chip.npwm = SP7021_PWM_NUM;
ret = devm_pwmchip_add(dev, &priv->chip);
if (ret < 0)
return dev_err_probe(dev, ret, "Cannot register sunplus PWM\n");
return 0;
}
static const struct of_device_id sunplus_pwm_of_match[] = {
{ .compatible = "sunplus,sp7021-pwm", },
{}
};
MODULE_DEVICE_TABLE(of, sunplus_pwm_of_match);
static struct platform_driver sunplus_pwm_driver = {
.probe = sunplus_pwm_probe,
.driver = {
.name = "sunplus-pwm",
.of_match_table = sunplus_pwm_of_match,
},
};
module_platform_driver(sunplus_pwm_driver);
MODULE_DESCRIPTION("Sunplus SoC PWM Driver");
MODULE_AUTHOR("Hammer Hsieh <hammerh0314@gmail.com>");
MODULE_LICENSE("GPL");